N-hydroxyethylamino- and n-morpholino-dithiocarboxylated cephalosporins

ABSTRACT

A-THIENYLMETHYL N - METHYL - N - B - HYDROXYETHYLDITHIOCARBAMATE, A-THIENYLMETHYL N, N - BIS(B-HYDROXYETHYL)DITHIOCARBAMATE, AND A-THIENYLMETHL MORPHOLINODITHIOCARBOXYLATE CEPHALOSPORINS USEFUL AS ANTIBIOTICS.

Patented Mar. 30, 1971 3,573 298 N-HYDROXYETHYLAMINO- AND N-MOR- PHOLINO-DITHIOCARBOXYLATED CEPH- ALOSPORINS Earle M. Van Heyningen, Indianapolis, Ind., and Carter W. Brown, Columbus, Ohio, assignors to Eli Lilly and Company, Indianapolis, Ind.

No Drawing. Original application Jan. 18, 1965, Ser. No. 426,391. Divided and this application Nov. 18, 1968, Ser. No. 776,792

Int. Cl. C07d 99/24 US. Cl. 260-243 3 Claims ABSTRACT OF THE DISCLOSURE a-Thienylmethyl N methyl N B hydroxyethyldithiocarbamate, a-thienylmethyl N,N bis(B-hydroxyethyl)dithiocarbamate, and a-thienylmethyl morpholinodithiocarboxylate cephalosporins useful as antibiotics.

CROSS-REFERENCE This application is a division of application Ser. No. 426,391, filed Jan. 18, 1965.

DETAILED DESCRIPTION OF THE INVENTION This invention relates to novel organic compounds and to methods for their preparation and use.

The novel compounds of the present invention are antibiotic substances having the characteristic ring structure of cephalosporin C but having a dithiocarbamatederived moiety in the 3 position instead of the ace'toxymethyl group of cephalosporin C. The novel compounds are represented by the following formula:

R CHzC NH( 3H-( 3 (IJHZ s /R o oN /G-CHr-S-CN\ o R t JOOH in which R is hydorogen, C -C alkyl, C -C alkoxy, C -C alkylmercapto, phenyl, phenoxy, phenylmercapto, thienyl, furyl, benzothienyl, or benzofuryl;

R taken separately, is C -C alkyl;

R taken separately, is C -C alkyl or C C cycloalkyl;

R and R taken together with the nitrogen atom to which they are attached, are pyrrolidino, piperidino, or morpholino; and

R and R contain a total of not more than eight carbon atoms.

Also included within the scope of the invention are the salts of the above compounds with pharmaceutically acceptable cations.

As used herein, alkyl refers broadly to primary, secondary, and tertiary alkyl, of both straight-chain and branched-chain configuration, wherein the number of carbon atoms therein is within the designated range, including methyl, 'ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec.-buty1, tert.-butyl, n-amyl, isoamyl, Z-amyl, 3-amyl, neopentyl, n-hexyl, isohexyl, 2-hexy1, and (where within the range) n-heptyl, isoheptyl, S-heptyl, Z-methylhexyl, and the like.

Alkoxy refers to alkyl--O groups wherein the alkyl moiety is as defined above.

Alkylmercapto refers to alkylS- groups wherein the alkyl moiety is as defined above.

Thienyl, benzothienyl, furyl, and benzofuryl groups may be attached at either the on or [3 position.

Cycloalkyl refers to cyclopropyl, cyclobutyl, cyclopentyl, or cyclohexyL,

Pharmaceutically acceptable cations refers to the positive ionic forms of sodium, potassium, lithium, calcium, barium, magnesium, aluminum, and other metals of acceptably low toxicity level, as well as the metalloid ammonium and a variety of organic nitrogen bases, including methylammonium, dimethylammonium, trimethylammonium, tetrarnethylammonium, choline, the ethylarnmoniums, procaine, quinine, dibenzylethylenediamine, and the like.

Halo, as used hereinafter, refers to fluoro, chloro, bromo, or iodo.

In naming the novel compounds of the invention, it is convenient to designate the characteristic saturated fusedring ,B-lactam thiazine structure of the cephalosporins as s p and to name the compounds as derivatives thereof, the term cephem referring to the basic ring structure with a single olefinic bond. According to this system, cephalosporin C itself would be named 7-(5-aminoadipamido)- 3 acetoxymethyl 3 cephem 4 carboxylic acid. More informally, it is convenient to name the compounds as derivatives of a hypothetical compound, 7-amino-3- cephem-4-carboxy1ic acid, and to specify the differences therefrom by naming the radical attached to the CO-NH- group in the 7 position and the dithiocarr bamate which is employed to replace the acetoxy group in the 3 position. Thus, 7 a thienylacetamido 3 (diethylaminothiocarbonylthiomethyl) 3 cephem 4 carboxylic acid is more simply designated as oz-thienylmethyl N,N-diethyldithiocarbamate cephalosporin.

Illustrative of the compounds lying within the scope of the present invention are the following examples, which may exist either as the free acids or as salts with non-toxic pharmaceutically acceptable cations:

7 -isovaleramido-3-(piperidinothiocarbonylthiomethyl)- 3-cephem-4-carboxy1ic acid 7 -,B-thienylacetamido-3 N-methyl-N-( 3 -amy1) aminothiocarbonylthiomethyl) -3-cephem-4-carboxylic acid 7-caprylamido-3-(N-methyl-N-cyclobutylaminothiocarbonylthiomethyl)-3-cephem-4-carboxylic acid 7-n-butyramido-3-(N-methyl-N-ethylaminothiocarbonylthiomethyl)-3-cephem-4-carboxylic acid 7-propionamido-3 (N-methyl-N-n-amylaminothiocarbonylthiomethyl)-3-cephem-4-carboxylic acid 7-acetamido-3-(dimethylaminothiocarbonylthiomethyl)- 3-cephem-4-carboxy1ic acid 7-ethoxyacetamido-3-(N-methyl-N-isohexylaminothiocarbonylthiomethyl)-3-cephem-4-carboxylic acid 7-n-nonanoarnido-3-(N-methyl-N-cyclopropylaminothiocarbonylthiomethyl) -3-cephem-4-carboxylic acid 7-isocaproamido-3-(N-methyl-N-isopropylaminothiocarbonylthiomethyl)-3-cephem-4-carboxylic acid 7-u-benzothienylacetamido-3- (N-ethyl-N- (Z-amyl) aminothiocarbonylthiomethyl) -3-cephem-4-carboxylic acid 7 -methoxyacetamido-3- (N-ethyl-N- 2-hexyl) aminothiocarbonylthiomethyl) -3 -cephem-4-carboxylic acid 7-B-furylacetamido-3-(N-methyl-N-cyclohexylaminothiocarbonylthiomethyl)-3-cephem-4-carboxylic acid 7-methy1rnercaptoacetamido-3-(N-ethyl N n propylaminothiocarbonylthiomethyl)-3-cephem-4-carboxylic acid 7-n-valeramido-3-(di-n-butylaminothiocabonylthiomethyl)-3-cephem-4-carboxylic acid 7-,8-benzothienylacetamido-3-(N-methyl N tert.-amylaminothiocarbonylthiomethyl) -3 -cephem-4-carboxylic acid 7-phenylacetamido-3-(diethylaminothiocarbonylthiomethyl)-3-cephem-4-carboxylic acid 7-a-furylacetamido-3 (N-ethyl-N-isobutylaminothiocarbonylthiomethyl)-3-cephem-4-carboxylic acid 7 -n-butylmercaptoacetamido-3- (pyrrolidinothiocarbonylthiomethyl)-3-cephem-4-carboxylic acid 7-a-benzofurylacetamido-3-(N ethyl N (3-methyl-2- butyl) -aminothiocarbonylthiomethyl) -3 -cephem-4 carboxylic acid 7-hexyloxyacetamido-3-(di-n-propylaminothiocarbonylthiomethyl) -3-cephem-4-carboxylic acid 7-phenoxyacetamido-3- (N-methyl-N- (2-butyl) aminothiocarbonylthiomethyl-3-cephem-4-carboxylic acid 7-neopentylcarboxamido-3-(diethylaminothiocarbonylthiomethyl)-3-cephem-4-carboxylic acid 7-phenylmercaptoacetamido-3-(N methyl N isobutylaminothiocarbonylthiomethyl) -3 -cephem-4-carboxylic acid 7-a-thienylacetamido-3-(N ethyl N cyclopentylaminothiocarbonylthiomethyl)-3-cephem-4-carboxylic acid 7-ethylmercapto acetamido-3- (di-n-propylaminothiocarbonylthiomethyl)-3-cephem-4-carboxylic acid While the compounds of the present invention have been defined in terms of a structural formula which depicts the novel structural features of the claimed compounds and which indicates the presence therein of certain well-known organic radicals, including alkyl, cycloalkyl, phenyl, thienyl, benzothienyl, furyl benzofuryl, pyrrolidino, piperidino, and morpholino, it will be recognized by those skilled in the art that such radicals may hear one or more substituents without departing in any way from the spirit of the invention and without altering the properties of the novel compounds in such a way as would set them apart from the invention or take them outside its scope. Compounds having the novel structure of the present invention and hearing such substituents are accordingly to be considered as equivalents of the unsubstituted compounds and are to be considered to lie within the scope of the invention. Among such substituent atoms and radicals are halo, hydroxy, nitro, lower alkyl, trifiuoromethyl, methoxy, methylmercapto, cyano, hydroxymethyl, ,B-hydroxyethyl, acetyl, acetamido, and the like.

The compounds of the present invention are readily prepared from an appropriate derivative of 7-aminocephalosporanic acid (i.e., a derivative thereof having the desired acylamido group in the 7 position and the characteristic acetoxymethyl group in the 3 position) by displacement of the acetoxyl group with a dithiocarbamate of appropriate structure. The reaction is conveniently carried out by dissolving a salt of the 7-aminocephalosporanic acid compound in water, adding an aqueous solution of an alkali-metal salt of the dithiocarbamate, preferably in at least a small molar excess, and stirring and Warming at ordinary or somewhat elevated temperature for several hours. The reaction may be carried out at temperatures between about 25 and about 100 C., preferably around 40 to 60 C., and for periods of about one to about 24 hours or more, the time necessary for complete reaction varying inversely With the temperature, and extended reaction times being without adverse effect under the preferred temperature conditions. The products thus obtained are generally water soluble, but may be salted out as a yellow glass by adding sodium chloride to about 50 percent of saturation, under which conditions the starting materials and by-products remain largely in solution. Many of the products are readily purified by dissolving in chloroform, washing with 50 percentsaturated aqueous sodium chloride solution to remove impurities, diluting with ether, and crystallizing.

As an alternative method, 7-aminocephalosporanic acid can be reacted with the dithiocarbamate, and the resulting intermediate can be reacted With an appropriate acylating agent to introduce the desired substituent in the 7 position.

The desired cephalosporin C starting material, having the acetoxymethyl group in the 3 position, is readily prepared by means now well-known in the art. The most convenient and economical method involves acylating 7-aminocephalosporanic acid with an acylating agent having the desired structure under conventional conditions. A convenient acylating agent is, for example, the appropriate R -substituted acetyl chloride or bromide. The acylation is carried out in water or in an appropriate organic solvent, preferably under substantially neutral conditions and preferably at reduced temperature, i.e., above the freezing point of the reaction mixture and up to about 20 C. In a typical procedure, 7-arninocephalosporanic acid is commingled with aqueous 50 volumepercent acetone and a sufficient quantity of sodium bicarbonate to promote solution, the concentration of 7-aminocephalosporanic acid being about one to about four percent by weight. The solution is cooled to around 0 to 5 C., and a solution of the acylating agent is added in about 20 percent excess, with sirring and cooling. The mixture is then allowed to warm to room temperature, after which it is acidified to around pH 2 and extracted with ethyl acetate or other immiscible organic solvent. The ethyl acetate extract is adjusted to around pH 4.5 with potassium hydroxide or other base and is backextracted into water. The water solution is separated and evaporated to dryness. The residue is taken up in the minimum quantity of water, and the acylated product is precipitated by adding a large excess of acetone and, if necessary, ether. The crystalline material obtained thereby is filtered, washed with acetone, and dried.

The dithiocarbamates employed in the present invention are conveniently prepared by the method of Bogemann, Methoden der Organischen Chemie (Houben- Weyl), Stuttgart: Georg Thiems Verlag, 1955, volume 9, page 826. A solution of sodium hydroxide (0.2 mole) in 35 ml. of water is cooled to 0 C. and mixed with an amine (0.2 mole) of the appropriate structure. Then carbon disulfide (0.2 mole) is added dropwise and the mixture is stirred for one hour. The dithiocarbamate precipitates as the sodium salt from the reaction mixture and is filtered off, air dried, and recrystallized from ethyl acetate or methanol-ether. The products are obtained in yields ranging from 60 to percent of theory. This technique is readily applicable to the preparation of the alkali-metal salts of N,N-dimethyl, N,N-diethyl, N-methyl-N-fl-hydroxyethyl, N,N-bis(,B-hydroxyethyl), N,N-din-butyl, N-methyl-N-cyclopentyl, N-ethyl-N-cyclohexyl, pyrrolidino, piperidino, and the other dithiocarbamates employed in the present invention.

The invention will be more readily understood from the following operating examples, which are submitted as illustrations only, and not by way of limitation.

In all cases, the following procedure was employed with only slight variations to preparethe designated compound. A 0.0012 mole portion of the appropriately substituted sodium 7-acylamidocephalosporanate and an equimolar amount of the appropriate sodium dithiocarbamate were dissolved in 10 ml. of water and heated at 40-45 C. in a thermostated oil bath for 24 hours, at the end of which time the solution was generally clear. The product was precipitated as a yellow glass by addition of an equal volume of aqueous saturated sodium chloride solution and chilling for several hours. The supernatant solution was decanted from the solid phase and the solid was dissolved in 25 to 50 ml. of chloroform. The chloroform solution was washed about 10 times with successive 12- 15 ml. portions of 50 percent saturated aqueous sodium chloride solution. In some cases, esjecially toward the end of the wash, troublesome emulsions were formed,

but were readily broken by centrifuging. The washing was conveniently followed by qualitative ultraviolet sepctra of the wash solutions; disappearance of the spectrum for starting material and appearance of the spectrum for the product indicated when washing was complete. The *Washed chloroform solution was evaporated; to half volume or less, then diluted with ether, and chilled. The sodium salt of the desired product separated as a fine powder, which was centrifuged and dried under vacuum.

The melting points of the products were not sharp, owing to the fact that the compounds tend to decompose at or around their melting point, and the melting points therefore vary, depending upon the temperature of the melting-point block when the compounds were first applied. All of the products, however, had infrared spectra consistent with the expected structure and gave one spot against Bacillus subtilz's in bio-autographs of paper chromatograms, which were developed with methyl ethyl ketone saturated with water. These data, together with the ultraviolet spectra, titrations, and analyses, were sufiicient to characterize the substances fully.

EXAMPLE 1 a-Thienylmethyl N-methyl-N-[i-hydroxyethyldi. thiocarbamate cephalosporin 7-a-thienylacetamido-3-(N methyl-N-fi-hydroxyethylaminothiocarbonylthiomethyl) 3 cephem-4-carboxylic acid sodium salt was obtained from 7-a-thienylacetamidocephalosporanic acid and sodium N-methyl-N-B-hydroxyethyldithiocarbarnate. Recrystallization was from methanol-isopropanol. Yield, 11.5 percent of theory. pK' 5.0. Ultraviolet absorption maxima at 233 and 271 m (6: 17,800 and 20,200, respectively).

Analysis.Calcd. (percent): C, 42.42; H, 3.95; N, 8.25. Found (percent): C, 42.62; H, 3.98; N, 8.13.

EXAMPLE 2 u-Thienylmethyl N,N-bis ,B-hydroxyethyl) dithiocarbamate cephalosporin 7-u-thienylacetarnido-3 (bis(p hydroxyethyl)aminothiocarbonylthiomethyl)-3-cephem-4-carboxylic acid sodium salt was obtained from 7-a-thienylacetamidocephalosporanic acid and sodium N,N-bis(fl-hydroxyethyDdithiocarbamate. The reaction product mixture was acidified to pH 2 and extracted into ethyl acetate. The extract was evaporated to dryness under vacuum. The residue was triturated with chloroform, then dissolved in methyl Cellosolve and methanol (3:1), adjusted to pH 6.5 with 1 N sodium hydroxide, and again evaporated to dryness. The residue was recrystallized from methanol-isopro panol. Yield, 6.8 percent of theory. pK' 5.0. Ultraviolet absorption maxima at 235 and 270 m (e: 15,000 and 11,750, respectively).

Analysis.Calcd. (percent): C, 42.28; H, 4.10; N, 7.79. Found (percent): C, 42.54; H, 3.90; N, 7.53.

EXAMPLE 3 a-Thienyl methyl morpholinodithiocarboxylate cephalosporin 7-a-thienylacetamido-3 (morpholinothiocarbonylthio methyl)-3-cephemr4-carboxylic acid sodium salt was obtained from 7-u-thienylacetamidocephalosporanic acid and sodium morpholinodithiocarboxylate. Yield, 14 percent of theory, pK 5.05. Ultraviolet absorption maxima at 230 and 274 m, (e=16,660 and 24,000, respectively).

The compounds of the present invention are antibiotic substances characterized by resistance to the destructive action of penicillinase, high activity against a variety of Gram-positive pathogens, and a lesser degree of activity against many of the Gram-negative pathogens.

We claim:

1. 7-a-thienylacetamido 3-(N methyl-N-B-hydroxyethylaminothiocarbonylthiomethyl) 3 cephem-4-carboxylic acid.

2. 7-a-thienylacetamido 3 (bis (fi-hydroxyethyl) aminothiocarbonylthiomethyl) 3 cephem-4-carb0xyic acid.

3. 7-a-thienylacetamido 3 (morpholinothiocarbonylthiomethyl)-3-cephem-4-carboxylic acid.

References Cited UNITED STATES PATENTS 3,258,461 '6/1966 Cooker et al. 2602A3C NICHOLAS S. RIZZO, Primary Examiner US. Cl. X.R. 260999 

